Rack and pinion type retractors are commonly used to hold a surgical incision open to provide access to the interior of the body. Retractor arms which can support various kinds of retractor blades are suspended over or rest on the patient. Generally, one arm is fixed and the other arm moves along a rack under the influence of a pinion driven by a rotatable handle. However, in certain retractors, both arms move with the rack. The handle is turned to operate a pinion against a rack and move one of the arms away from the other to open the wound under the influence of retractor blades which are inserted through the incision. Often large forces are experienced by the retractor. Since the retractor arms extend from the rack significant forces and moments can be developed at the point where the movable arm extends from the rack. The arm and the housing from which it extends tend to rotate about its supporting rack under the influence of the retraction forces. This rotation can cause undesirable metal-to-metal contact with significant force between various parts of the retractor which can make it difficult to operate the retractor and can subject the metal from which the retractor is made to high stresses which can cause undesirable wear to the parts.
It would be desirable to have a bearing system which could distribute the forces to which the retractor parts are subjected during use.